/**
 * @copyright
 * Copyright (C) 2020 Assured Information Security, Inc.
 *
 * @copyright
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * @copyright
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * @copyright
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

    .code64
    .intel_syntax noprefix

    .globl  serial_write_c
    .type   serial_write_c, @function
serial_write_c:
    push rax
    push rdx

wait_for_ffio_empty:
    mov rdx, HYPERVISOR_SERIAL_PORT
    add rdx, 5
    in  al, dx

    and al, 0x20
    cmp al, 0x0
    jz  wait_for_ffio_empty

    mov rdx, HYPERVISOR_SERIAL_PORT
    mov rax, rdi
    out dx, al

    pop rdx
    pop rax
    ret
    int 3

    .size serial_write_c, .-serial_write_c
